Regiospecific synthesis of symmetrical (1E,3E) 2,3-difluoro-1,4-diphenyl-buta-1,3-dienes via palladium-catalyzed cross-coupling of (Z) 2-bromo-2-fluoroethenylbenzenes in presence of bis(pinacolato)diboron

Eddarir, Saïd; Rolando, Christian

doi:10.1016/j.jfluchem.2003.08.004

Cited by 11 publications

(4 citation statements)

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“…The cross-coupling reaction of ( Z )-1-bromo-1-fluoroalkenes catalyzed by PdCl 2 (PPh 3 ) 2 ·2PPh 3 (3 mol %) and CsF in THF in the presence of bis(pinacolato)diboron led to 1,4-disubstituted ( E , E )-2,3-difluorobuta-1,3-dienes 443 in high yields and stereoselectivities (Scheme ) …”

Section: Metal-catalyzed Reactions Of Gem-dihalovinyl Systemsmentioning

confidence: 99%

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

2011

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Vinyl halides 24 and 25 were prepared from the tribromoromethyl carbinol 23, obtained in turn by reaction of benzo[b]thiophene-2-carboxaldehyde with the tribromomethane anion 43 generated in situ from 2,2,2-tribromoethanoic acid in DMSO (Scheme 24). 44 The intermediate 23 was treated with SOCl 2 or Et 2 NSF 3 to give the vinyl halides 24 (33% yield) or 25 (32% yield) through halogenation followed by dehydrobromination.2.1.3. Substitution Reactions. Although the most common source for gem-dibromoalkenes are carbonyl compounds, there are some examples in which alkene and alkyne derivatives have been used as starting materials. Reaction of longifolene 26 and camphene 29 with Hg(OAc) 2 /NaCl resulted in the isolation of vinylic dimercurichlorides 27 and 30, respectively (Scheme 25). These organometallics by treatment with Br 2 in pyridine afforded the related gem-dibromoalkenes 28 and 31 in very high yields. 45 Recently, 1,1-dibromo-2-arylethenes have been readily obtained in good yields (66À90%) via double ipso-bromo desilylation with N-bromosuccinimide (NBS) of 1,1-bis(trimethylsilyl)-2arylethenes, which were in turn easily obtained in high yields by Heck coupling of aryliodides with ethene-1,1-diylbis(trimethylsilane) (Scheme 26). 46 Interestingly, 1,1-bis(trimethylsilyl)-2-alkenylethenes, for example, 1,1-bis(trimethylsilyl)-4-phenylbuta-1,3-diene, under the same reaction conditions led to the selective formation of the dibrominated products containing 1,3-diene fragments.A variety of gem-dibromides were prepared from stannyl acetylenes (Scheme 27). These compounds by treatment with 1.4 equiv of Cp 2 Zr(H)Cl generated the related 1,1-heterobimetallic species of tin and zirconium, which by brominolysis with 2.5 equiv of Br 2 in CCl 4 or 3.0 equiv of N-bromosuccinimide at room temperature gave the corresponding dibromides in 53À83% yields. 47 2.1.4. Miscellaneous Reactions. Nenajdenko and co-workers reported an efficient one-pot transformation of a wide range of aldehydes and ketones into the corresponding dibromoalkenes via intermediate formation of the related hydrazones (Scheme 28). 48 Thus, these carbonyl compounds were treated with hydrazine hydrate, and when the starting materials disappeared, CBr 4 and catalytic CuCl were added to give the target products in 43À97% yields from aldehydes 48a and 43À97% yields from linear, cyclic, and caged ketones, 48a depending on the steric hindrance of the staring material. Analogously, a wide range of hydrazones of (hetero)aryl alkyl ketones (electron-rich and electron-poor) was converted into the related dibromoalkenes in 23À92% yields. 48b The proposed mechanism of the reaction starts from the oxidation of CuCl with CBr 4 to give a Cu(II) salt, which in turn oxidizes the hydrazone to the diazoalkane (Scheme 28). Decomposition of the diazoalkane generates a copperÀcarbene complex, which by interaction with CBr 4 finally leads to the dibromoalkene.

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Section: Metal-catalyzed Reactions Of Gem-dihalovinyl Systemsmentioning

confidence: 99%

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

2011

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“…Interestingly, when 1,1-dibromoalkenes reacted with B 2 pin 2 with the assistance of n -butyllithium at −110 °C, 1,1-diborylalkenes were obtained . It should be noted that when an alkenyl halide containing both an alkene C–F and C–Br bond such as ( Z )-(2-bromo-2-fluorovinyl)benzene was used as a substrate, the borylation reaction took place selectively at the C–Br bond and the C–F bond remained intact …”

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Cu-Catalyzed Stereoselective Borylation of gem-Difluoroalkenes with B₂pin₂

et al. 2017

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“…However few synthetic methods are available for the preparation of symmetrical fluorinated dienes: McCarthy and co-workers have reported symmetrical fluorinated dienes from palladium-catalyzed coupling reactions between (a-fluoro) vinyl stannanes and phenyl triflate, oxalyl chloride, and ethyl chloroformate [21,22]. Wnuk and co-workers also obtained symmetrical fluorinated dienes in the palladium-catalyzed coupling reactions between (a-fluoro) vinyl tris(trimethylsilyl)germanes and aryl or alkenyl halides [23]; recently Rolando and co-workers reported the synthesis of (1E, 3E)-2,3-difluoro-1,4-disubstituted-buta-1,3-dienes from (Z)-1-bromo-1-fluoroalkenes in the presence of bis(pinacolato)diborane and Cl 2 Pd(PPh 3 ) 2 [24]. Herein, we detail the preparation of both (1Z, 3Z)-and (1E, 3E)-2,3-difluoro-1,4-disubstituted-buta-1, 3-dienes via the Pd(PPh 3 ) 4 /Bu 3 SnSnBu 3 -mediated homocoupling of 1-bromo-1-fluoroalkenes.…”

Section: Introductionmentioning

confidence: 99%

Stereospecific preparation of symmetrical (1Z, 3Z)- and (1E, 3E)-2,3-difluoro-1,4-disubstituted-buta-1,3-dienes from 1-bromo-1-fluoroalkenes

Burton

2007

Journal of Fluorine Chemistry

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Regiospecific synthesis of symmetrical (1E,3E) 2,3-difluoro-1,4-diphenyl-buta-1,3-dienes via palladium-catalyzed cross-coupling of (Z) 2-bromo-2-fluoroethenylbenzenes in presence of bis(pinacolato)diboron

Cited by 11 publications

References 33 publications

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

Cu-Catalyzed Stereoselective Borylation of gem-Difluoroalkenes with B₂pin₂

Stereospecific preparation of symmetrical (1Z, 3Z)- and (1E, 3E)-2,3-difluoro-1,4-disubstituted-buta-1,3-dienes from 1-bromo-1-fluoroalkenes

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Regiospecific synthesis of symmetrical (1E,3E) 2,3-difluoro-1,4-diphenyl-buta-1,3-dienes via palladium-catalyzed cross-coupling of (Z) 2-bromo-2-fluoroethenylbenzenes in presence of bis(pinacolato)diboron

Cited by 11 publications

References 33 publications

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

Synthesis and Metal-Catalyzed Reactions of gem-Dihalovinyl Systems

Cu-Catalyzed Stereoselective Borylation of gem-Difluoroalkenes with B2pin2

Stereospecific preparation of symmetrical (1Z, 3Z)- and (1E, 3E)-2,3-difluoro-1,4-disubstituted-buta-1,3-dienes from 1-bromo-1-fluoroalkenes

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Cu-Catalyzed Stereoselective Borylation of gem-Difluoroalkenes with B₂pin₂